The durability of subsea tunnels under the coupled action of stress and chloride ions\nwas analyzed to estimate the service life and provide a theoretical foundation for durability design.\nThe influence coefficient of the stress on chloride ion transmission at lower stress levels was discussed\naccording to the material mechanics, and was verified by experimental data. A stress calculation model\nof a subsea tunnelâ??s lining section is proposed based on the plane-section assumption. Considering\nthe space-time effect of the convection velocity, a partial differential equation was constructed to\ncalculate the chloride ion transfer condition under the coupled action of stress-convection-diffusion.\nThe numerical solution of the partial differential equation was solved and the sensitivity of the\nparameters was analyzed. The subsea tunnelâ??s time-varying reliability index was calculated following\nthe Monte Carlo method, and was used to predict the service life. The results show that the chloride\nion concentration calculated by considering the coupled action is larger and the reliability index is\nlower than calculated only considering diffusion. Our findings contribute to the conclusion that\ndurability designs of subsea tunnels should consider the coupled action of stress-convection-diffusion.\nAn effective method to improve the service life of a subsea tunnel is to reduce the water-binder ratio\nor increase the thickness of protective cover.
Loading....